Polymers functionalized with polyimine compounds

ABSTRACT

A method for preparing a functionalized polymer, the method comprising the steps of (i) polymerizing conjugated diene monomer by employing a lanthanide-based catalyst to form a reactive polymer, and (ii) reacting the reactive polymer with a polyimine compound.

FIELD OF THE INVENTION

One or more embodiments of the present invention relates tofunctionalized polymers and methods for their manufacture.

BACKGROUND OF THE INVENTION

In the art of manufacturing tires, it is desirable to employ rubbervulcanizates that give reduced hysteresis, i.e., less loss of mechanicalenergy to heat. For example, rubber vulcanizates that show reducedhysteresis are advantageously employed in tire components, such assidewalls and treads, to yield tires having desirably low rollingresistance. The hysteresis of a rubber vulcanizate is often attributedto the free polymer chain ends within the crosslinked rubber network, aswell as the dissociation of filler agglomerates. Functionalized polymershave been employed to reduce hysteresis. The functional group of thefunctionalized polymer may reduce the number of free polymer chain endsvia interaction with filler particles. Also, the functional group mayreduce filler agglomeration. Nevertheless, whether a particularfunctional group imparted to a polymer can reduce hysteresis is oftenunpredictable.

Functionalized polymers may be prepared by post-polymerization treatmentof reactive polymers with certain functionalizing agents. However,whether a reactive polymer can be functionalized by treatment with aparticular functionalizing agent can be unpredictable. For example,functionalizing agents that work for one type of polymer do notnecessarily work for another type of polymer, and vice versa.

Lanthanide-based catalyst systems are known to be useful forpolymerizing conjugated diene monomers to form polydienes having highcis-1,4 linkage contents. The resulting cis-1,4-polydienes may displaypseudo-living characteristics in that, upon completion of thepolymerization, some of the polymer chains possess reactive ends thatcan react with certain functionalizing agents to yield functionalizedcis-1,4-polydienes.

The cis-1,4-polydines produced with lanthanide-based catalysts have alinear backbone, which is believed to provide better tensile properties,higher abrasion resistance, lower hysteresis, and better fatigueresistance as compared to the cis-1,4-polydienes prepared with othercatalyst systems such as titanium-, cobalt-, and nickel-based catalystsystems. Therefore, the cis-1,4-polydienes made with lanthanide-basedcatalysts are particularly suitable for use in tire components such assidewalls and treads. However, one disadvantage of thecis-1,4-polydienes prepared with lanthanide-based catalysts is that thepolymers exhibit relatively high cold flow due to their linear backbonestructure. The high cold flow causes problems during storage andtransport of the polymers and also hinders the use of automatic feedingequipment in rubber compound mixing facilities.

Therefore, there is a need to develop a method for producinglanthanide-catalyzed cis-1,4-polydienes that give reduced hysteresis aswell as improved cold flow resistance.

SUMMARY OF THE INVENTION

One or more embodiments of the present invention provide a method forpreparing a functionalized polymer, the method comprising the steps ofpolymerizing conjugated diene monomer by employing a lanthanide-basedcatalyst to form a reactive polymer, and reacting the reactive polymerwith a polyimine compound, where the polyimine compound is defined bythe formula I:

where m is an integer of 3 or more, R¹ is a divalent organic group, R²is a monovalent organic group or hydrogen atom, and μ is a polyvalentatom or organic group having a valence equal to m; or the formula II:

where n is an integer of 2 or more, R¹ is a divalent organic group, R³is a divalent organic group or a chemical bond, μ is a polyvalent atomor organic group having a valence equal to n, θ is a heterocyclic group,and R⁴ is a hydrogen atom, a monovalent organic group, or a heterocyclicgroup.

Other embodiments provide a method for preparing a functionalizedpolymer, the method comprising the steps of introducing conjugated dienemonomer and a lanthanide-based catalyst to form a polymerizationmixture, and adding a polyimine compound to the polymerization mixture,where the polyimine compound is defined by the formula I:

where m is an integer of 3 or more, R¹ is a divalent organic group, R²is a monovalent organic group or hydrogen atom, and μ is a polyvalentatom or organic group having a valence equal to m; or the formula II:

where n is an integer of 2 or more, R¹ is a divalent organic group, R³is a divalent organic group or a chemical bond, μ is a polyvalent atomor organic group having a valence equal to n, θ is a heterocyclic group,and R⁴ is a hydrogen atom, a monovalent organic group, or a heterocyclicgroup.

Other embodiments provide a functionalized polymer prepared by a methodcomprising the steps of polymerizing conjugated diene monomer byemploying a lanthanide-based catalyst to form a reactive polymer, andreacting the reactive polymer with a polyimine compound, where thepolyimine compound is defined by the formula I:

where m is an integer of 3 or more, R¹ is a divalent organic group, R²is a monovalent organic group or hydrogen atom, and μ is a polyvalentatom or organic group having a valence equal to m; or the formula II:

where n is an integer of 2 or more, R¹ is a divalent organic group, R³is a divalent organic group or a chemical bond, μ is a polyvalent atomor organic group having a valence equal to n, θ is a heterocyclic group,and R⁴ is a hydrogen atom, a monovalent organic group, or a heterocyclicgroup.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical plot of cold-flow gauge (mm @ 8 min) versus Mooneyviscosity (ML 1+4 at 100° C.) for functionalized cis-1,4-polybutadieneprepared according to one or more embodiments of the present inventionas compared to unfunctionalized cis-1,4-polybutadiene.

FIG. 2 is a graphical plot of hysteresis loss (tan δ) versus Mooneyviscosity (ML 1+4 at 130° C.) for vulcanizates prepared fromfunctionalized cis-1,4-polybutadiene prepared according to one or moreembodiments of the present invention as compared to vulcanizatesprepared from unfunctionalized cis-1,4-polybutadiene.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

According to one or more embodiments of the present invention,conjugated diene monomer can be polymerized with a lanthanide-basedcatalyst system to form a pseudo-living polymer, and this polymer canthen be functionalized by reaction with a polyimine compound. Theresultant functionalized polydiene can be used in the manufacture oftire components. In one or more embodiments, the resultantfunctionalized polydienes, which include cis-1,4-polydienes, exhibitadvantageous cold-flow resistance and provide tire components thatexhibit advantageously low hysteresis.

Examples of conjugated diene monomer include 1,3-butadiene, isoprene,1,3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-1,3-butadiene,2-ethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene,4-methyl-1,3-pentadiene, and 2,4-hexadiene. Mixtures of two or moreconjugated dienes may also be utilized in copolymerization.

Practice of one or more embodiments of the present invention is notlimited by the selection of any particular lanthanide-based catalyst. Inone or more embodiments, the catalyst composition may include alanthanide compound, an alkylating agent, and a halogen-containingcompound that includes one or more labile halogen atoms. Where thelanthanide compound and/or alkylating agent include one or more labilehalogen atoms, the catalyst need not include a separatehalogen-containing compound; e.g., the catalyst may simply include ahalogenated lanthanide compound and an alkylating agent. In certainembodiments, the alkylating agent may include both an aluminoxane and atleast one other organoaluminum compound. In yet other embodiments, acompound containing a non-coordinating anion, or a non-coordinatinganion precursor, i.e., a compound that can undergo a chemical reactionto form a non-coordinating anion, may be employed in lieu of ahalogen-containing compound. In one embodiment, where the alkylatingagent includes an organoaluminum hydride compound, thehalogen-containing compound may be a tin halide as disclosed in U.S.Pat. No. 7,008,899, which is incorporated herein by reference. In theseor other embodiments, other organometallic compounds, Lewis bases,and/or catalyst modifiers may be employed in addition to the ingredientsor components set forth above. For example, in one embodiment, anickel-containing compound may be employed as a molecular weightregulator as disclosed in U.S. Pat. No. 6,699,813, which is incorporatedherein by reference.

Various lanthanide compounds or mixtures thereof can be employed. In oneor more embodiments, these compounds may be soluble in hydrocarbonsolvents such as aromatic hydrocarbons, aliphatic hydrocarbons, orcycloaliphatic hydrocarbons. In other embodiments, hydrocarbon-insolublelanthanide compounds, which can be suspended in the polymerizationmedium to form the catalytically active species, are also useful.

Lanthanide compounds may include at least one atom of lanthanum,neodymium, cerium, praseodymium, promethium, samarium, europium,gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium,lutetium, and didymium. Didymium may include a commercial mixture ofrare-earth elements obtained from monazite sand.

The lanthanide atom in the lanthanide compounds can be in variousoxidation states including but not limited to the 0, +2, +3, and +4oxidation states. Lanthanide compounds include, but are not limited to,lanthanide carboxylates, lanthanide organophosphates, lanthanideorganophosphonates, lanthanide organophosphinates, lanthanidecarbamates, lanthanide dithiocarbamates, lanthanide xanthates,lanthanide β-diketonates, lanthanide alkoxides or aryloxides, lanthanidehalides, lanthanide pseudo-halides, lanthanide oxyhalides, andorganolanthanide compounds.

Without wishing to limit the practice of the present invention, furtherdiscussion will focus on neodymium compounds, although those skilled inthe art will be able to select similar compounds that are based uponother lanthanide metals.

Neodymium carboxylates include neodymium formate, neodymium acetate,neodymium acrylate, neodymium methacrylate, neodymium valerate,neodymium gluconate, neodymium citrate, neodymium fumarate, neodymiumlactate, neodymium maleate, neodymium oxalate, neodymium2-ethylhexanoate, neodymium neodecanoate (a.k.a. neodymium versatate),neodymium naphthenate, neodymium stearate, neodymium oleate, neodymiumbenzoate, and neodymium picolinate.

Neodymium organophosphates include neodymium dibutyl phosphate,neodymium dipentyl phosphate, neodymium dihexyl phosphate, neodymiumdiheptyl phosphate, neodymium dioctyl phosphate, neodymiumbis(1-methylheptyl)phosphate, neodymium bis(2-ethylhexyl)phosphate,neodymium didecyl phosphate, neodymium didodecyl phosphate, neodymiumdioctadecyl phosphate, neodymium dioleyl phosphate, neodymium diphenylphosphate, neodymium bis(p-nonylphenyl)phosphate, neodymiumbutyl(2-ethylhexyl)phosphate,neodymium(1-methylheptyl)(2-ethylhexyl)phosphate, andneodymium(2-ethylhexyl)(p-nonylphenyl)phosphate.

Neodymium organophosphonates include neodymium butyl phosphonate,neodymium pentyl phosphonate, neodymium hexyl phosphonate, neodymiumheptyl phosphonate, neodymium octyl phosphonate,neodymium(1-methylheptyl)phosphonate,neodymium(2-ethylhexyl)phosphonate, neodymium decyl phosphonate,neodymium dodecyl phosphonate, neodymium octadecyl phosphonate,neodymium oleyl phosphonate, neodymium phenyl phosphonate,neodymium(p-nonylphenyl)phosphonate, neodymium butyl butylphosphonate,neodymium pentyl pentylphosphonate, neodymium hexyl hexylphosphonate,neodymium heptyl heptylphosphonate, neodymium octyl octylphosphonate,neodymium(1-methylheptyl)(1-methylheptyl)phosphonate,neodymium(2-ethylhexyl)(2-ethylhexyl)phosphonate, neodymium decyldecylphosphonate, neodymium dodecyl dodecylphosphonate, neodymiumoctadecyl octadecylphosphonate, neodymium oleyl oleylphosphonate,neodymium phenyl phenylphosphonate,neodymium(p-nonylphenyl)(p-nonylphenyl)phosphonate, neodymiumbutyl(2-ethylhexyl)phosphonate, neodymium(2-ethylhexyl)butylphosphonate,neodymium(1-methylheptyl)(2-ethylhexyl)phosphonate,neodymium(2-ethylhexyl)(1-methylheptyl)phosphonate,neodymium(2-ethylhexyl)(p-nonylphenyl)phosphonate, andneodymium(p-nonylphenyl)(2-ethylhexyl)phosphonate.

Neodymium organophosphinates include neodymium butylphosphinate,neodymium pentylphosphinate, neodymium hexylphosphinate, neodymiumheptylphosphinate, neodymium octylphosphinate, neodymium(1-methylheptyl)phosphinate, neodymium(2-ethylhexyl)phosphinate,neodymium decylphosphinate, neodymium dodecylphosphinate, neodymiumoctadecylphosphinate, neodymium oleylphosphinate, neodymiumphenylphosphinate, neodymium(p-nonylphenyl)phosphinate, neodymiumdibutylphosphinate, neodymium dipentylphosphinate, neodymiumdihexylphosphinate, neodymium diheptylphosphinate, neodymiumdioctylphosphinate, neodymium bis(1-methylheptyl)phosphinate, neodymiumbis(2-ethylhexyl)phosphinate, neodymium didecylphosphinate, neodymiumdidodecylphosphinate, neodymium dioctadecylphosphinate, neodymiumdioleylphosphinate, neodymium diphenylphosphinate, neodymiumbis(p-nonylphenyl)phosphinate, neodymium butyl(2-ethylhexyl)phosphinate,neodymium(1-methylheptyl)(2-ethylhexyl)phosphinate, andneodymium(2-ethylhexyl)(p-nonylphenyl)phosphinate.

Neodymium carbamates include neodymium dimethylcarbamate, neodymiumdiethylcarbamate, neodymium diisopropylcarbamate, neodymiumdibutylcarbamate, and neodymium dibenzylcarbamate.

Neodymium dithiocarbamates include neodymium dimethyldithiocarbamate,neodymium diethyldithiocarbamate, neodymium diisopropyldithiocarbamate,neodymium dibutyldithiocarbamate, and neodymium dibenzyldithiocarbamate.

Neodymium xanthates include neodymium methylxanthate, neodymiumethylxanthate, neodymium isopropylxanthate, neodymium butylxanthate, andneodymium benzylxanthate.

Neodymium β-diketonates include neodymium acetylacetonate, neodymiumtrifluoroacetylacetonate, neodymium hexafluoroacetylacetonate, neodymiumbenzoylacetonate, and neodymium 2,2,6,6-tetramethyl-3,5-heptanedionate.

Neodymium alkoxides or aryloxides include neodymium methoxide, neodymiumethoxide, neodymium isopropoxide, neodymium 2-ethylhexoxide, neodymiumphenoxide, neodymium nonylphenoxide, and neodymium naphthoxide.

Neodymium halides include neodymium fluoride, neodymium chloride,neodymium bromide, and neodymium iodide. Suitable neodymiumpseudo-halides include neodymium cyanide, neodymium cyanate, neodymiumthiocyanate, neodymium azide, and neodymium ferrocyanide. Suitableneodymium oxyhalides include neodymium oxyfluoride, neodymiumoxychloride, and neodymium oxybromide. Where neodymium halides,neodymium oxyhalides, or other neodymium compounds containing labilehalogen atoms are employed, the neodymium-containing compound can alsoserve as the halogen-containing compound. A Lewis base such astetrahydrofuran (THF) may be employed as an aid for solubilizing thisclass of neodymium compounds in inert organic solvents.

The term organolanthanide compound may refer to any lanthanide compoundcontaining at least one lanthanide-carbon bond. These compounds arepredominantly, though not exclusively, those containing cyclopentadienyl(Cp), substituted cyclopentadienyl, allyl, and substituted allylligands. Suitable organolanthanide compounds include Cp₃Ln, Cp₂LnR,Cp₂LnCl, CpLnCl₂, CpLn(cyclooctatetraene), (C₅Me₅)₂LnR, LnR₃,Ln(allyl)₃, and Ln(allyl)₂Cl, where Ln represents a lanthanide atom, andR represents a hydrocarbyl group.

Various alkylating agents, or mixtures thereof, can be used. Alkylatingagents, which may also be referred to as hydrocarbylating agents,include organometallic compounds that can transfer hydrocarbyl groups toanother metal. Typically, these agents include organometallic compoundsof electropositive metals such as Groups 1, 2, and 3 metals (Groups IA,IIA, and IIIA metals). In one or more embodiments, alkylating agentsinclude organoaluminum and organomagnesium compounds. Where thealkylating agent includes a labile halogen atom, the alkylating agentmay also serve as the halogen-containing compound.

The term “organoaluminum compound” may refer to any aluminum compoundcontaining at least one aluminum-carbon bond. In one or moreembodiments, organoaluminum compounds may be soluble in a hydrocarbonsolvent.

In one or more embodiments, organoaluminum compounds include thoserepresented by the formula AlR_(n)X_(3−n), where each R, which may bethe same or different, is a mono-valent organic group that is attachedto the aluminum atom via a carbon atom, where each X, which may be thesame or different, is a hydrogen atom, a halogen atom, a carboxylategroup, an alkoxide group, or an aryloxide group, and where n is aninteger of 1 to 3. In one or more embodiments, each R may be ahydrocarbyl group such as, but not limited to, alkyl, cycloalkyl,substituted cycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl,aryl, substituted aryl, aralkyl, alkaryl, allyl, and alkynyl groups.These hydrocarbyl groups may contain heteroatoms such as, but notlimited to, nitrogen, oxygen, boron, silicon, sulfur, and phosphorusatoms.

Organoaluminum compounds include, but are not limited to,trihydrocarbylaluminum, dihydrocarbylaluminum hydride,hydrocarbylaluminum dihydride, dihydrocarbylaluminum carboxylate,hydrocarbylaluminum bis(carboxylate), dihydrocarbylaluminum alkoxide,hydrocarbylaluminum dialkoxide, dihydrocarbylaluminum halide,hydrocarbylaluminum dihalide, dihydrocarbylaluminum aryloxide, andhydrocarbylaluminum diaryloxide compounds.

Trihydrocarbylaluminum compounds include trimethylaluminum,triethylaluminum, triisobutylaluminum, tri-n-propylaluminum,triisopropylaluminum, tri-n-butylaluminum, tri-t-butylaluminum,tri-n-pentylaluminum, trineopentylaluminum, tri-n-hexylaluminum,tri-n-octylaluminum, tris(2-ethylhexyl)aluminum, tricyclohexylaluminum,tris(1-methylcyclopentyl)aluminum, triphenylaluminum,tri-p-tolylaluminum, tris(2,6-dimethylphenyl)aluminum,tribenzylaluminum, diethylphenylaluminum, diethyl-p-tolylaluminum,diethylbenzylaluminum, ethyldiphenylaluminum, ethyldi-p-tolylaluminum,and ethyldibenzylaluminum.

Dihydrocarbylaluminum hydride compounds include diethylaluminum hydride,di-n-propylaluminum hydride, diisopropylaluminum hydride,di-n-butylaluminum hydride, diisobutylaluminum hydride,di-n-octylaluminum hydride, diphenylaluminum hydride, di-p-tolylaluminumhydride, dibenzylaluminum hydride, phenylethylaluminum hydride,phenyl-n-propylaluminum hydride, phenylisopropylaluminum hydride,phenyl-n-butylaluminum hydride, phenylisobutylaluminum hydride,phenyl-n-octylaluminum hydride, p-tolylethylaluminum hydride,p-tolyl-n-propylaluminum hydride, p-tolylisopropylaluminum hydride,p-tolyl-n-butylaluminum hydride, p-tolylisobutylaluminum hydride,p-tolyl-n-octylaluminum hydride, benzylethylaluminum hydride,benzyl-n-propylaluminum hydride, benzylisopropylaluminum hydride,benzyl-n-butylaluminum hydride, benzylisobutylaluminum hydride, andbenzyl-n-octylaluminum hydride.

Hydrocarbylaluminum dihydrides include ethylaluminum dihydride,n-propylaluminum dihydride, isopropylaluminum dihydride, n-butylaluminumdihydride, isobutylaluminum dihydride, and n-octylaluminum dihydride.

Dihydrocarbylaluminum chloride compounds include diethylaluminumchloride, di-n-propylaluminum chloride, diisopropylaluminum chloride,di-n-butylaluminum chloride, diisobutylaluminum chloride,di-n-octylaluminum chloride, diphenylaluminum chloride,di-p-tolylaluminum chloride, dibenzylaluminum chloride,phenylethylaluminum chloride, phenyl-n-propylaluminum chloride,phenylisopropylaluminum chloride, phenyl-n-butylaluminum chloride,phenylisobutylaluminum chloride, phenyl-n-octylaluminum chloride,p-tolylethylaluminum chloride, p-tolyl-n-propylaluminum chloride,p-tolylisopropylaluminum chloride, p-tolyl-n-butylaluminum chloride,p-tolylisobutylaluminum chloride, p-tolyl-n-octylaluminum chloride,benzylethylaluminum chloride, benzyl-n-propylaluminum chloride,benzylisopropylaluminum chloride, benzyl-n-butylaluminum chloride,benzylisobutylaluminum chloride, and benzyl-n-octylaluminum chloride.

Hydrocarbylaluminum dichloride include ethylaluminum dichloride,n-propylaluminum dichloride, isopropylaluminum dichloride,n-butylaluminum dichloride, isobutylaluminum dichloride, andn-octylaluminum dichloride.

Other organoaluminum compounds include dimethylaluminum hexanoate,diethylaluminum octoate, diisobutylaluminum 2-ethylhexanoate,dimethylaluminum neodecanoate, diethylaluminum stearate,diisobutylaluminum oleate, methylaluminum bis(hexanoate), ethylaluminumbis(octoate), isobutylaluminum bis(2-ethylhexanoate), methylaluminumbis(neodecanoate), ethylaluminum bis(stearate), isobutylaluminumbis(oleate), dimethylaluminum methoxide, diethylaluminum methoxide,diisobutylaluminum methoxide, dimethylaluminum ethoxide, diethylaluminumethoxide, diisobutylaluminum ethoxide, dimethylaluminum phenoxide,diethylaluminum phenoxide, diisobutylaluminum phenoxide, methylaluminumdimethoxide, ethylaluminum dimethoxide, isobutylaluminum dimethoxide,methylaluminum diethoxide, ethylaluminum diethoxide, isobutylaluminumdiethoxide, methylaluminum diphenoxide, ethylaluminum diphenoxide,isobutylaluminum diphenoxide, and the like, and mixtures thereof.

Another class of organoaluminum compounds include aluminoxanes.Aluminoxanes include oligomeric linear aluminoxanes that can berepresented by the general formula:

and oligomeric cyclic aluminoxanes that can be represented by thegeneral formula:

where x may be an integer of 1 to about 100, and in other embodimentsabout 10 to about 50; y may be an integer of 2 to about 100, and inother embodiments about 3 to about 20; and where each R¹, which may bethe same or different, may be a mono-valent organic group that isattached to the aluminum atom via a carbon atom. In one or moreembodiments, each R¹ is a hydrocarbyl group such as, but not limited to,alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, cycloalkenyl,substituted cycloalkenyl, aryl, substituted aryl, aralkyl, alkaryl,allyl, and alkynyl groups. These hydrocarbyl groups may containheteroatoms such as, but not limited to, nitrogen, oxygen, boron,silicon, sulfur, and phosphorus atoms. It should be noted that thenumber of moles of the aluminoxane as used in this application refers tothe number of moles of the aluminum atoms rather than the number ofmoles of the oligomeric aluminoxane molecules. This convention iscommonly employed in the art of catalysis utilizing aluminoxanes.

Aluminoxanes can be prepared by reacting trihydrocarbylaluminumcompounds with water. This reaction can be performed according to knownmethods, such as (1) a method in which the trihydrocarbylaluminumcompound may be dissolved in an organic solvent and then contacted withwater, (2) a method in which the trihydrocarbylaluminum compound may bereacted with water of crystallization contained in, for example, metalsalts, or water adsorbed in inorganic or organic compounds, and (3) amethod in which the trihydrocarbylaluminum compound may be reacted withwater in the presence of the monomer or monomer solution that is to bepolymerized.

Aluminoxane compounds include methylaluminoxane (MAO), modifiedmethylaluminoxane (MMAO), ethylaluminoxane, n-propylaluminoxane,isopropylaluminoxane, butylaluminoxane, isobutylaluminoxane,n-pentylaluminoxane, neopentylaluminoxane, n-hexylaluminoxane,n-octylaluminoxane, 2-ethylhexylaluminoxane, cylcohexylaluminoxane,1-methylcyclopentylaluminoxane, phenylaluminoxane,2,6-dimethylphenylaluminoxane, and the like, and mixtures thereof.Modified methylaluminoxane can be formed by substituting about 20-80% ofthe methyl groups of methylaluminoxane with C₂ to C₁₂ hydrocarbylgroups, preferably with isobutyl groups, by using techniques known tothose skilled in the art.

Aluminoxanes can be used alone or in combination with otherorganoaluminum compounds. In one embodiment, methylaluminoxane and atleast one other organoaluminum compound (e.g., AlR_(n)X_(3−n)) such asdiisobutyl aluminum hydride are employed in combination.

The term organomagnesium compound may refer to any magnesium compoundthat contains at least one magnesium-carbon bond. Organomagnesiumcompounds may be soluble in a hydrocarbon solvent. One class oforganomagnesium compounds that can be utilized may be represented by theformula MgR₂, where each R, which may be the same or different, is amono-valent organic group, with the proviso that the group is attachedto the magnesium atom via a carbon atom. In one or more embodiments,each R may be a hydrocarbyl group, and the resulting organomagnesiumcompounds are dihydrocarbylmagnesium compounds. Examples of thehydrocarbyl groups include, but are not limited to, alkyl, cycloalkyl,substituted cycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl,aryl, allyl, substituted aryl, aralkyl, alkaryl, and alkynyl groups.These hydrocarbyl groups may contain heteroatoms such as, but notlimited to, nitrogen, oxygen, silicon, sulfur, and phosphorus atom.

Examples of suitable dihydrocarbylmagnesium compounds includediethylmagnesium, di-n-propylmagnesium, diisopropylmagnesium,dibutylmagnesium, dihexylmagnesium, diphenylmagnesium,dibenzylmagnesium, and mixtures thereof.

Another class of organomagnesium compounds that can be utilized includethose that may be represented by the formula RMgX, where R is amono-valent organic group, with the proviso that the group is attachedto the magnesium atom via a carbon atom, and X is a hydrogen atom, ahalogen atom, a carboxylate group, an alkoxide group, or an aryloxidegroup. In one or more embodiments, R may be a hydrocarbyl group such as,but not limited to, alkyl, cycloalkyl, substituted cycloalkyl, alkenyl,cycloalkenyl, substituted cycloalkenyl, aryl, allyl, substituted aryl,aralkyl, alkaryl, and alkynyl groups. These hydrocarbyl groups maycontain heteroatoms such as, but not limited to, nitrogen, oxygen,boron, silicon, sulfur, and phosphorus atoms. In one or moreembodiments, X is a carboxylate group, an alkoxide group, or anaryloxide group.

Exemplary types of organomagnesium compounds that can be represented bythe formula RMgX include, but are not limited to, hydrocarbylmagnesiumhydride, hydrocarbylmagnesium halide, hydrocarbylmagnesium carboxylate,hydrocarbylmagnesium alkoxide, hydrocarbylmagnesium aryloxide, andmixtures thereof.

Specific examples of organomagnesium compounds that may be representedby the formula RMgX include methylmagnesium hydride, ethylmagnesiumhydride, butylmagnesium hydride, hexylmagnesium hydride, phenylmagnesiumhydride, benzylmagnesium hydride, methylmagnesium chloride,ethylmagnesium chloride, butylmagnesium chloride, hexylmagnesiumchloride, phenylmagnesium chloride, benzylmagnesium chloride,methylmagnesium bromide, ethylmagnesium bromide, butylmagnesium bromide,hexylmagnesium bromide, phenylmagnesium bromide, benzylmagnesiumbromide, methylmagnesium hexanoate, ethylmagnesium hexanoate,butylmagnesium hexanoate, hexylmagnesium hexanoate, phenylmagnesiumhexanoate, benzylmagnesium hexanoate, methylmagnesium ethoxide,ethylmagnesium ethoxide, butylmagnesium ethoxide, hexylmagnesiumethoxide, phenylmagnesium ethoxide, benzylmagnesium ethoxide,methylmagnesium phenoxide, ethylmagnesium phenoxide, butylmagnesiumphenoxide, hexylmagnesium phenoxide, phenylmagnesium phenoxide,benzylmagnesium phenoxide, and the like, and mixtures thereof.

Various halogen-containing compounds, or mixtures thereof, that containone or more labile halogen atoms can be employed. Examples of halogenatoms include, but are not limited to, fluorine, chlorine, bromine, andiodine. A combination of two or more halogen-containing compounds havingdifferent halogen atoms can also be utilized. In one or moreembodiments, the halogen-containing compounds may be soluble in ahydrocarbon solvent. In other embodiments, hydrocarbon-insolublehalogen-containing compounds, which can be suspended in thepolymerization medium to form the catalytically active species, may beuseful.

Suitable types of halogen-containing compounds include, but are notlimited to, elemental halogens, mixed halogens, hydrogen halides,organic halides, inorganic halides, metallic halides, organometallichalides, and mixtures thereof.

Elemental halogens include fluorine, chlorine, bromine, and iodine.Mixed halogens include iodine monochloride, iodine monobromide, iodinetrichloride, and iodine pentafluoride.

Hydrogen halides include hydrogen fluoride, hydrogen chloride, hydrogenbromide, and hydrogen iodide.

Organic halides include t-butyl chloride, t-butyl bromides, allylchloride, allyl bromide, benzyl chloride, benzyl bromide,chloro-di-phenylmethane, bromo-di-phenylmethane, triphenylmethylchloride, triphenylmethyl bromide, benzylidene chloride, benzylidenebromide, methyltrichlorosilane, phenyltrichlorosilane,dimethyldichlorosilane, diphenyldichlorosilane, trimethylchlorosilane,benzoyl chloride, benzoyl bromide, propionyl chloride, propionylbromide, methyl chloroformate, and methyl bromoformate.

Inorganic halides include phosphorus trichloride, phosphorus tribromide,phosphorus pentachloride, phosphorus oxychloride, phosphorus oxybromide,boron trifluoride, boron trichloride, boron tribromide, silicontetrafluoride, silicon tetrachloride, silicon tetrabromide, silicontetraiodide, arsenic trichloride, arsenic tribromide, arsenic triiodide,selenium tetrachloride, selenium tetrabromide, tellurium tetrachloride,tellurium tetrabromide, and tellurium tetraiodide.

Metallic halides include tin tetrachloride, tin tetrabromide, aluminumtrichloride, aluminum tribromide, antimony trichloride, antimonypentachloride, antimony tribromide, aluminum triiodide, aluminumtrifluoride, gallium trichloride, gallium tribromide, gallium triiodide,gallium trifluoride, indium trichloride, indium tribromide, indiumtriiodide, indium trifluoride, titanium tetrachloride, titaniumtetrabromide, titanium tetraiodide, zinc dichloride, zinc dibromide,zinc diiodide, and zinc difluoride.

Organometallic halides include dimethylaluminum chloride,diethylaluminum chloride, dimethylaluminum bromide, diethylaluminumbromide, dimethylaluminum fluoride, diethylaluminum fluoride,methylaluminum dichloride, ethylaluminum dichloride, methylaluminumdibromide, ethylaluminum dibromide, methylaluminum difluoride,ethylaluminum difluoride, methylaluminum sesquichloride, ethylaluminumsesquichloride, isobutylaluminum sesquichloride, methylmagnesiumchloride, methylmagnesium bromide, methylmagnesium iodide,ethylmagnesium chloride, ethylmagnesium bromide, butylmagnesiumchloride, butylmagnesium bromide, phenylmagnesium chloride,phenylmagnesium bromide, benzylmagnesium chloride, trimethyltinchloride, trimethyltin bromide, triethyltin chloride, triethyltinbromide, di-t-butyltin dichloride, di-t-butyltin dibromide, dibutyltindichloride, dibutyltin dibromide, tributyltin chloride, and tributyltinbromide.

Compounds containing non-coordinating anions are known in the art. Ingeneral, non-coordinating anions are sterically bulky anions that do notform coordinate bonds with, for example, the active center of a catalystsystem due to steric hindrance. Exemplary non-coordinating anionsinclude tetraarylborate anions and fluorinated tetraarylborate anions.Compounds containing a non-coordinating anion also contain a countercation such as a carbonium, ammonium, or phosphonium cation. Exemplarycounter cations include triarylcarbonium cations andN,N-dialkylanilinium cations. Examples of compounds containing anon-coordinating anion and a counter cation include triphenylcarboniumtetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, triphenylcarboniumtetrakis[3,5-bis(trifluoromethyl)phenyl]borate, andN,N-dimethylanilinium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate.

Non-coordinating anion precursors include compounds that can form anon-coordinating anion under reaction conditions. Exemplarynon-coordinating anion precursors include triarylboron compounds, BR₃,where R is a strong electron-withdrawing aryl group such as apentafluorophenyl or 3,5-bis(trifluoromethyl)phenyl group.

The catalyst composition used in this invention may be formed bycombining or mixing the foregoing catalyst ingredients. Although one ormore active catalyst species are believed to result from the combinationof the catalyst ingredients, the degree of interaction or reactionbetween the various catalyst ingredients or components is not known withany great degree of certainty. Therefore, the term “catalystcomposition” has been employed to encompass a simple mixture of theingredients, a complex of the various ingredients that is caused byphysical or chemical forces of attraction, a chemical reaction productof the ingredients, or a combination of the foregoing.

The foregoing catalyst composition may have high catalytic activity forpolymerizing conjugated dienes into cis-1,4-polydienes over a wide rangeof catalyst concentrations and catalyst ingredient ratios. Severalfactors may impact the optimum concentration of any one of the catalystingredients. For example, because the catalyst ingredients may interactto form an active species, the optimum concentration for any onecatalyst ingredient may be dependent upon the concentrations of theother catalyst ingredients.

In one or more embodiments, the molar ratio of the alkylating agent tothe lanthanide compound (alkylating agent/Ln) can be varied from about1:1 to about 1,000:1, in other embodiments from about 2:1 to about500:1, and in other embodiments from about 5:1 to about 200:1.

In those embodiments where both an aluminoxane and at least one otherorganoaluminum agent are employed as alkylating agents, the molar ratioof the aluminoxane to the lanthanide compound (aluminoxane/Ln) can bevaried from 5:1 to about 1,000:1, in other embodiments from about 10:1to about 700:1, and in other embodiments from about 20:1 to about 500:1;and the molar ratio of the at least one other organoaluminum compound tothe lanthanide compound (Al/Ln) can be varied from about 1:1 to about200:1, in other embodiments from about 2:1 to about 150:1, and in otherembodiments from about 5:1 to about 100:1.

The molar ratio of the halogen-containing compound to the lanthanidecompound is best described in terms of the ratio of the moles of halogenatoms in the halogen-containing compound to the moles of lanthanideatoms in the lanthanide compound (halogen/Ln). In one or moreembodiments, the halogen/Ln molar ratio can be varied from about 0.5:1to about 20:1, in other embodiments from about 1:1 to about 10:1, and inother embodiments from about 2:1 to about 6:1.

In yet another embodiment, the molar ratio of the non-coordinating anionor non-coordinating anion precursor to the lanthanide compound (An/Ln)may be from about 0.5:1 to about 20:1, in other embodiments from about0.75:1 to about 10:1, and in other embodiments from about 1:1 to about6:1.

The catalyst composition can be formed by various methods.

In one embodiment, the catalyst composition may be formed in situ byadding the catalyst ingredients to a solution containing monomer andsolvent, or to bulk monomer, in either a stepwise or simultaneousmanner. In one embodiment, the alkylating agent can be added first,followed by the lanthanide compound, and then followed by thehalogen-containing compound, if used, or by the compound containing anon-coordinating anion or the non-coordinating anion precursor.

In another embodiment, the catalyst composition may be preformed. Thatis, the catalyst ingredients are pre-mixed outside the polymerizationsystem either in the absence of any monomer or in the presence of asmall amount of at least one conjugated diene monomer at an appropriatetemperature, which may be from about −20° C. to about 80° C. The amountof conjugated diene monomer that may be used for preforming the catalystcan range from about 1 to about 500 moles, in other embodiments fromabout 5 to about 250 moles, and in other embodiments from about 10 toabout 100 moles per mole of the lanthanide compound. The resultingcatalyst composition may be aged, if desired, prior to being added tothe monomer that is to be polymerized.

In yet another embodiment, the catalyst composition may be formed byusing a two-stage procedure. The first stage may involve combining thealkylating agent with the lanthanide compound either in the absence ofany monomer or in the presence of a small amount of at least oneconjugated diene monomer at an appropriate temperature, which may befrom about −20° C. to about 80° C. The amount of monomer employed in thefirst stage may be similar to that set forth above for performing thecatalyst. In the second stage, the mixture formed in the first stage andthe halogen-containing compound, non-coordinating anion, ornon-coordinating anion precursor can be charged in either a stepwise orsimultaneous manner to the monomer that is to be polymerized.

In one or more embodiments, a solvent may be employed as a carrier toeither dissolve or suspend the catalyst or catalyst ingredients in orderto facilitate the delivery of the catalyst or catalyst ingredients tothe polymerization system. In other embodiments, conjugated dienemonomer can be used as the catalyst carrier. In yet other embodiments,the catalyst ingredients can be used in their neat state without anysolvent.

In one or more embodiments, suitable solvents include those organiccompounds that will not undergo polymerization or incorporation intopropagating polymer chains during the polymerization of monomer in thepresence of catalyst. In one or more embodiments, these organic speciesare liquid at ambient temperature and pressure. In one or moreembodiments, these organic solvents are inert to the catalyst. Exemplaryorganic solvents include hydrocarbons with a low or relatively lowboiling point such as aromatic hydrocarbons, aliphatic hydrocarbons, andcycloaliphatic hydrocarbons. Non-limiting examples of aromatichydrocarbons include benzene, toluene, xylenes, ethylbenzene,diethylbenzene, and mesitylene. Non-limiting examples of aliphatichydrocarbons include n-pentane, n-hexane, n-heptane, n-octane, n-nonane,n-decane, isopentane, isohexanes, isopentanes, isooctanes,2,2-dimethylbutane, petroleum ether, kerosene, and petroleum spirits.And, non-limiting examples of cycloaliphatic hydrocarbons includecyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane.Mixtures of the above hydrocarbons may also be used. As is known in theart, aliphatic and cycloaliphatic hydrocarbons may be desirably employedfor environmental reasons. The low-boiling hydrocarbon solvents aretypically separated from the polymer upon completion of thepolymerization.

Other examples of organic solvents include high-boiling hydrocarbons ofhigh molecular weights, such as paraffinic oil, aromatic oil, or otherhydrocarbon oils that are commonly used to oil-extend polymers. Sincethese hydrocarbons are non-volatile, they typically do not requireseparation and remain incorporated in the polymer.

The production of polymer according to this invention can beaccomplished by polymerizing conjugated diene monomer in the presence ofa catalytically effective amount of the foregoing catalyst composition.The introduction of the catalyst composition, the conjugated dienemonomer, and any solvent if employed forms a polymerization mixture inwhich the polymer product is formed. The total catalyst concentration tobe employed in the polymerization mixture may depend on the interplay ofvarious factors such as the purity of the ingredients, thepolymerization temperature, the polymerization rate and conversiondesired, the molecular weight desired, and many other factors.Accordingly, a specific total catalyst concentration cannot bedefinitively set forth except to say that catalytically effectiveamounts of the respective catalyst ingredients can be used. In one ormore embodiments, the amount of the lanthanide compound used can bevaried from about 0.01 to about 2 mmol, in other embodiments from about0.02 to about 1 mmol, and in other embodiments from about 0.05 to about0.5 mmol per 100 g of conjugated diene monomer.

In one or more embodiments, the polymerization of conjugated dienemonomer according to this invention may be carried out in apolymerization system that includes a substantial amount of solvent. Inone embodiment, a solution polymerization system may be employed inwhich both the monomer to be polymerized and the polymer formed aresoluble in the solvent. In another embodiment, a precipitationpolymerization system may be employed by choosing a solvent in which thepolymer formed is insoluble. In both cases, an amount of solvent inaddition to the amount of solvent that may be used in preparing thecatalyst is usually added to the polymerization system. The additionalsolvent may be the same as or different from the solvent used inpreparing the catalyst. Exemplary solvents have been set forth above. Inone or more embodiments, the solvent content of the polymerizationmixture may be more than 20% by weight, in other embodiments more than50% by weight, and in still other embodiments more than 80% by weightbased on the total weight of the polymerization mixture.

In other embodiments, the polymerization system employed may begenerally considered a bulk polymerization system that includessubstantially no solvent or a minimal amount of solvent. Those skilledin the art will appreciate the benefits of bulk polymerization processes(i.e., processes where monomer acts as the solvent), and therefore thepolymerization system includes less solvent than will deleteriouslyimpact the benefits sought by conducting bulk polymerization. In one ormore embodiments, the solvent content of the polymerization mixture maybe less than about 20% by weight, in other embodiments less than about10% by weight, and in still other embodiments less than about 5% byweight based on the total weight of the polymerization mixture. In stillanother embodiment, the polymerization mixture is substantially devoidof solvent, which refers to the absence of that amount of solvent thatwould otherwise have an appreciable impact on the polymerizationprocess. Polymerization systems that are substantially devoid of solventmay be referred to as including substantially no solvent. In particularembodiments, the polymerization mixture is devoid of solvent.

The polymerization may be conducted in any conventional polymerizationvessels known in the art. In one or more embodiments, solutionpolymerization can be conducted in a conventional stirred-tank reactor.In other embodiments, bulk polymerization can be conducted in aconventional stirred-tank reactor, especially if the monomer conversionis less than about 60%. In still other embodiments, especially where themonomer conversion in a bulk polymerization process is higher than about60%, which typically results in a highly viscous cement, the bulkpolymerization may be conducted in an elongated reactor in which theviscous cement under polymerization is driven to move by piston, orsubstantially by piston. For example, extruders in which the cement ispushed along by a self-cleaning single-screw or double-screw agitatorare suitable for this purpose. Examples of useful bulk polymerizationprocesses are disclosed in U.S. Publication No. 2005/0197474 A1, whichis incorporated herein by reference.

In one or more embodiments, all of the ingredients used for thepolymerization can be combined within a single vessel (e.g., aconventional stirred-tank reactor), and all steps of the polymerizationprocess can be conducted within this vessel. In other embodiments, twoor more of the ingredients can be pre-combined in one vessel and thentransferred to another vessel where the polymerization of monomer (or atleast a major portion thereof) may be conducted.

The polymerization can be carried out as a batch process, a continuousprocess, or a semi-continuous process. In the semi-continuous process,the monomer is intermittently charged as needed to replace that monomeralready polymerized. In one or more embodiments, the conditions underwhich the polymerization proceeds may be controlled to maintain thetemperature of the polymerization mixture within a range from about −10°C. to about 200° C., in other embodiments from about 0° C. to about 150°C., and in other embodiments from about 20° C. to about 100° C. In oneor more embodiments, the heat of polymerization may be removed byexternal cooling by a thermally controlled reactor jacket, internalcooling by evaporation and condensation of the monomer through the useof a reflux condenser connected to the reactor, or a combination of thetwo methods. Also, conditions may be controlled to conduct thepolymerization under a pressure of from about 0.1 atmosphere to about 50atmospheres, in other embodiments from about 0.5 atmosphere to about 20atmosphere, and in other embodiments from about 1 atmosphere to about 10atmospheres. In one or more embodiments, the pressures at which thepolymerization may be carried out include those that ensure that themajority of the monomer is in the liquid phase. In these or otherembodiments, the polymerization mixture may be maintained underanaerobic conditions.

The polymers prepared by employing the lanthanide-based catalyst systemdisclosed herein may include reactive chain ends before thepolymerization mixture is quenched. These reactive polymers, which maybe referred to as pseudo-living polymers, can be reacted with apolyimine compound or mixtures thereof to form the functionalizedpolymers of this invention.

In one or more embodiments, polyimine compounds include those defined bythe formula I:

where m is an integer of 3 or more, R¹ is a divalent organic group, R²is a monovalent organic group or hydrogen atom, and μ is a polyvalentatom or organic group having a valence equal to m.

In other embodiments, polyimine compounds include those defined by theformula II:

where n is an integer of 2 or more, R¹ is a divalent organic group, R³is a divalent organic group or chemical bond, μ is a polyvalent atom ororganic group having a valence equal to n, θ is a heterocyclic group,and R⁴ is a hydrogen atom, a monovalent organic group, or a heterocyclicgroup.

In one or more embodiments, the monvalent organic groups may includehydrocarbyl groups or substituted hydrocarbyl groups such as, but notlimited to alkyl, cycloalkyl, substituted cycloalkyl, alkenyl,cycloalkenyl, substituted cycloalkenyl, aryl, allyl, substituted aryl,aralkyl, alkaryl, and alkynyl groups. In one or more embodiments, eachgroup may contain from 1 carbon atom, or the appropriate minimum numberof carbon atoms to form the group, up to 20 carbon atoms. Thesehydrocarbyl groups may contain heteroatoms such as, but not limited to,nitrogen, boron, oxygen, silicon, sulfur, and phosphorus atoms. In oneor more embodiments, one or more of R¹, R², R³, and R⁴ include aheterocyclic substituent.

In one or more embodiments, the divalent organic group may include ahydrocarbylene group or substituted hydrocarbylene group such as, butnot limited to, alkylene, cycloalkylene, substituted alkylene,substituted cycloalkylene, alkenylene, cycloalkenylene, substitutedalkenylene, substituted cycloalkenylene, arylene, and substitutedarylene groups. In one or more embodiments, each group may contain from1 carbon atom, or the appropriate minimum number of carbon atoms to formthe group, up to about 20 carbon atoms. Substituted hydrocarbylene groupincludes a hydrocarbylene group in which one or more hydrogen atoms havebeen replaced by a substituent such as an alkyl group. The divalentorganic groups may also contain one or more heteroatoms such as, but notlimited to, nitrogen, oxygen, boron, silicon, sulfur, and phosphorusatoms.

The heterocyclic group θ may contain one heteroatom or multipleheteroatoms that are either the same or distinct. In particularembodiments, the heteroatoms may be selected from the group consistingof nitrogen, oxygen, sulfur, boron, silicon, tin, and phosphorus atoms.Also, the heterocyclic group θ may be monocyclic, bicyclic, tricyclic ormulticyclic. In these or other embodiments, the heterocyclic group maycontain unsaturation and may be aromatic or non-aromatic.

Representative examples of unsaturated heterocyclic groups containingnitrogen heteroatoms include 2-pyridyl, 3-pyridyl, 4-pyridyl, pyrazinyl,2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 3-pyridazinyl,4-pyridazinyl, N-methyl-2-pyrrolyl, N-methyl-3-pyrrolyl,N-methyl-2-imidazolyl, N-methyl-4-imidazolyl, N-methyl-5-imidazolyl,N-methyl-3-pyrazolyl, N-methyl-4-pyrazolyl, N-methyl-5-pyrazolyl,N-methyl-1,2,3-triazol-4-yl, N-methyl-1,2,3-triazol-5-yl,N-methyl-1,2,4-triazol-3-yl, N-methyl-1,2,4-triazol-5-yl,1,2,4-triazin-3-yl, 1,2,4-triazin-5-yl, 1,2,4-triazin-6-yl,1,3,5-triazinyl, N-methyl-2-pyrrolin-2-yl, N-methyl-2-pyrrolin-3-yl,N-methyl-2-pyrrolin-4-yl, N-methyl-2-pyrrolin-5-yl,N-methyl-3-pyrrolin-2-yl, N-methyl-3-pyrrolin-3-yl,N-methyl-2-imidazolin-2-yl, N-methyl-2-imidazolin-4-yl,N-methyl-2-imidazolin-5-yl, N-methyl-2-pyrazolin-3-yl,N-methyl-2-pyrazolin-4-yl, N-methyl-2-pyrazolin-5-yl, 2-quinolyl,3-quinolyl, 4-quinolyl, 1-isoquinolyl, 3-isoquinolyl, 4-isoquinolyl,N-methylindol-2-yl, N-methylindol-3-yl, N-methylisoindol-1-yl,N-methylisoindol-3-yl, 1-indolizinyl, 2-indolizinyl, 3-indolizinyl,1-phthalazinyl, 2-quinazolinyl, 4-quinazolinyl, 2-quinoxalinyl,3-cinnolinyl, 4-cinnolinyl, 1-methylindazol-3-yl, 1,5-naphthyridin-2-yl,1,5-naphthyridin-3-yl, 1,5-naphthyridin-4-yl, 1,8-naphthyridin-2-yl,1,8-naphthyridin-3-yl, 1,8-naphthyridin-4-yl, 2-pteridinyl,4-pteridinyl, 6-pteridinyl, 7-pteridinyl, 1-methylbenzimidazol-2-yl,6-phenanthridinyl, N-methyl-2-purinyl, N-methyl-6-purinyl,N-methyl-8-purinyl, N-methyl-β-carbolin-1-yl, N-methyl-β-carbolin-3-yl,N-methyl-β-carbolin-4-yl, 9-acridinyl, 1,7-phenanthrolin-2-yl,1,7-phenanthrolin-3-yl, 1,7-phenanthrolin-4-yl, 1,10-phenanthrolin-2-yl,1,10-phenanthrolin-3-yl, 1,10-phenanthrolin-4-yl,4,7-phenanthrolin-1-yl, 4,7-phenanthrolin-2-yl, 4,7-phenanthrolin-3-yl,1-phenazinyl, 2-phenazinyl, pyrrolidino, and piperidino groups.

Representative examples of unsaturated heterocyclic groups containingoxygen heteroatoms include 2-furyl, 3-furyl, 2-benzo[b]furyl,3-benzo[b]furyl, 1-isobenzo[b]furyl, and 3-isobenzo[b]furyl,2-naphtho[2,3-b]furyl, and 3-naphtho[2,3-b]furyl groups.

Representative examples of unsaturated heterocyclic groups containingsulfur heteroatoms include 2-thienyl, 3-thienyl, 2-benzo[b]thienyl,3-benzo[b]thienyl, 1-isobenzo[b]thienyl, 3-isobenzo[b]thienyl,2-naphtho[2,3-b]thienyl, and 3-naphtho[2,3-b]thienyl groups.

Representative examples of unsaturated heterocyclic groups containingtwo or more distinct heteroatoms include 2-oxazolyl, 4-oxazolyl,5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 2-thiazolyl,4-thiazolyl, 5-thiazolyl, 3-isothiazolyl, 4-isothiazolyl,5-isothiazolyl, 1,2,3-oxadiazol-4-yl, 1,2,3-oxadiazol-5-yl,1,3,4-oxadiazol-2-yl, 1,2,3-thiadiazol-4-yl, 1,2,3-thiadiazol-5-yl,1,3,4-thiadiazol-2-yl, 2-oxazolin-2-yl, 2-oxazolin-4-yl,2-oxazolin-5-yl, 3-isoxazolinyl, 4-isoxazolinyl, 5-isoxazolinyl,2-thiazolin-2-yl, 2-thiazolin-4-yl, 2-thiazolin-5-yl, 3-isothiazolinyl,4-isothiazolinyl, 5-isothiazolinyl, 2-benzothiazolyl, and morpholinogroups.

In those embodiments where the polyimine is defined by the formula Iwith m being equal to 3, the polyimine compounds may be referred to astris-imine compounds. Specific examples of tris-imine compounds includeN,N′,N″-tris(benzylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(cyclohexylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(cyclopentylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(4-dimethylaminobenzylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(4-diethylaminobenzylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(4-di-n-butylaminobenzylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-methoxybenzylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(3-methoxybenzylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(4-methoxybenzylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-pyridylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(3-pyridylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(4-pyridylmethylidene)-tris(2-aminoethyl)amine,N-(2-pyridylmethylidene)-N′,N″-bis(benzylidene)-tris(2-aminoethyl)amine,N,N′-bis(2-pyridylmethylidene)-N″-(benzylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(pyrazinylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-pyrimidinylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(3-pyridazinylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1-methyl-2-pyrrolylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1-methyl-2-imidazolylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1-methyl-3-pyrazolylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-furylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(3-furylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-thienylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(3-thienylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-oxazolylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(3-isoxazolylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-thiazolylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(3-isothiazolylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1-methyl-1,2,3-triazol-4-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1-methyl-1,2,4-triazol-5-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1,2,3-oxadiazol-4-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1,3,4-oxadiazol-2-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1,3,5-triazinylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1-methyl-2-pyrrolin-2-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1-methyl-2-imidazolin-2-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1-methyl-2-pyrazolin-3-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-oxazolin-2-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-thiazolin-2-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-isothiazolin-2-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-quinolylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1-isoquinolylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1-methylindol-2-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-methylisoindol-1-ylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(1-phthalazinylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-quinazolinylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(2-quinoxalinylmethylidene)-tris(2-aminoethyl)amine,N,N′,N″-tris(3-cinnolinylmethylidene)-tris(2-aminoethyl)amine, andN,N′,N″-tris(2-benzothiazolylmethylidene)-tris(2-aminoethyl)amine.

In those embodiments where the polyimine compound is defined by theformula II with n being equal to 2, the polyimine compounds may bereferred to as heterocyclic bis-imine compounds. Specific examples ofheterocyclic bis-imine compounds includeN,N′-bis(2-pyridylmethylidene)ethylenediamine,N-(2-pyridylmethylidene)-N′-(benzylidene)ethylene diamine,N,N′-bis(3-pyridylmethylidene)ethylene diamine,N-(3-pyridylmethylidene)-N′-(benzylidene)ethylenediamine,N,N′-bis(4-pyridylmethylidene)ethylenediamine,N-(4-pyridylmethylidene)-N′-(benzylidene)ethylenediamine,N,N′-bis(pyrazinylmethylidene)ethylenediamine,N,N′-bis(2-pyrimidinylmethylidene)ethylenediamine,N,N′-bis(3-pyridazinylmethylidene)ethylene diamine,N,N′-bis(1-methyl-2-pyrrolylmethylidene)ethylene diamine,N,N′-bis(1-methyl-2-imidazolylmethylidene)ethylenediamine,N,N′-bis(1-methyl-3-pyrazolylmethylidene)ethylenediamine,N,N′-bis(2-furylmethylidene)ethylene diamine,N,N′-bis(3-furylmethylidene)ethylene diamine,N,N′-bis(2-thienylmethylidene)ethylenediamine,N,N′-bis(3-thienylmethylidene)ethylenediamine,N,N′-bis(2-oxazolylmethylidene)ethylenediamine,N,N′-bis(3-isoxazolylmethylidene)ethylenediamine,N,N′-bis(2-thiazolylmethylidene)ethylenediamine,N,N′-bis(3-isothiazolylmethylidene)ethylenediamine,N,N′-bis(1-methyl-1,2,3-triazol-4-ylmethylidene)ethylenediamine,N,N′-bis(1-methyl-1,2,4-triazol-5-ylmethylidene)ethylenediamine,N,N′-bis(1,2,3-oxadiazol-4-ylmethylidene)ethylenediamine,N,N′-bis(1,3,4-oxadiazol-2-ylmethylidene)ethylenediamine,N,N′-bis(1,3,5-triazinylmethylidene)ethylenediamine,N,N′-bis(1-methyl-2-pyrrolin-2-ylmethylidene)ethylenediamine,N,N′-bis(1-methyl-2-imidazolin-2-ylmethylidene)ethylenediamine,N,N′-bis(1-methyl-2-pyrazolin-3-ylmethylidene)ethylenediamine,N,N′-bis(2-oxazolin-2-ylmethylidene)ethylenediamine,N,N′-bis(2-thiazolin-2-ylmethylidene)ethylenediamine,N,N′-bis(2-isothiazolin-2-ylmethylidene)ethylene diamine,N,N′-bis(2-quinolylmethylidene)ethylenediamine,N,N′-bis(1-isoquinolylmethylidene)ethylenediamine,N,N′-bis(1-methylindol-2-ylmethylidene)ethylenediamine,N,N′-bis(2-methylisoindol-1-ylmethylidene)ethylenediamine,N,N′-bis(1-phthalazinylmethylidene)ethylenediamine,N,N′-bis(2-quinazolinylmethylidene)ethylenediamine,N,N′-bis(2-quinoxalinylmethylidene)ethylenediamine,N,N′-bis(3-cinnolinylmethylidene)ethylenediamine,N,N′-bis(2-benzothiazolylmethylidene)ethylenediamine,N,N′-bis(2-pyridylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(3-pyridylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(4-pyridylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(pyrazinylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-pyrimidinylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(3-pyridazinylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1-methyl-2-pyrrolylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1-methyl-2-imidazolylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1-methyl-3-pyrazolylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-furylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(3-furylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-thienylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(3-thienylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-oxazolylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(3-isoxazolylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-thiazolylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(3-isothiazolylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1-methyl-1,2,3-triazol-4-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1-methyl-1,2,4-triazol-5-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1,2,3-oxadiazol-4-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1,3,4-oxadiazol-2-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1,3,5-triazinylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1-methyl-2-pyrrolin-2-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1-methyl-2-imidazolin-2-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1-methyl-2-pyrazolin-3-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-oxazolin-2-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-thiazolin-2-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-isothiazolin-2-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-quinolylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1-isoquinolylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1-methylindol-2-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-methylisoindol-1-ylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(1-phthalazinylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-quinazolinylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(2-quinoxalinylmethylidene)-1,2-cyclohexanediamine,N,N′-bis(3-cinnolinylmethylidene)-1,2-cyclohexanediamine, andN,N′-bis(2-benzothiazolylmethylidene)-1,2-cyclohexanediamine.

The amount of the polyimine compound that can be reacted with thepseudo-living polymer may vary depending on the desired degree offunctionalization. In one or more embodiments, the amount of thepolyimine compound employed can be described with reference to thelanthanide metal of the lanthanide compound. For example, the molarratio of the polyimine compound to the lanthanide metal may be fromabout 1:1 to about 200:1, in other embodiments from about 5:1 to about150:1, and in other embodiments from about 10:1 to about 100:1.

In one or more embodiments, the pseudo-living polymer and the polyiminecompound can be reacted by combining or mixing them together. Forexample, where the pseudo-living polymer is synthesized in solution, thepolyimine compound can be added to the solution in which thepseudo-living polymer is prepared. In one or more embodiments, thepolyimine compound can be reacted with the pseudo-living polymer beforethe pseudo-living polymer is quenched. In one or more embodiments, thereaction between the polyimine compound and the pseudo-living polymermay take place within 30 minutes, in other embodiments within 5 minutes,and in other embodiments within one minute of reaching the peakpolymerization temperature resulting from the synthesis of thepseudo-living polymer. In one or more embodiments, the reaction betweenthe pseudo-living polymer and the polyimine compound can occur at thepeak polymerization temperature. In other embodiments, the reactionbetween the pseudo-living polymer and the polyimine compound can occurafter the pseudo-living polymer has been stored. In one or moreembodiments, the storage of the pseudo-living polymer occurs at roomtemperature or below under an inert atmosphere. In one or moreembodiments, the reaction between the polyimine compound and thepseudo-living polymer may take place at a temperature from about 10° C.to about 150° C., and in other embodiments from about 20° C. to about100° C.

In one or more embodiments, after the reaction between the pseudo-livingpolymer and the polyimine compound has been accomplished or completed, aquenching agent can be added to the polymerization mixture in order toinactivate any residual reactive polymer chains and the catalyst orcatalyst components. The quenching agent may include a protic compound,which includes, but is not limited to, an alcohol, a carboxylic acid, aninorganic acid, water, or a mixture thereof. An antioxidant such as2,6-di-tert-butyl-4-methylphenol may be added along with, before, orafter the addition of the quenching agent. The amount of the antioxidantemployed may be in the range of 0.2% to 1% by weight of the polymerproduct.

When the polymerization mixture has been quenched, the polymer productcan be recovered from the polymerization mixture by using anyconventional procedures of desolventization and drying that are known inthe art. For instance, the polymer can be recovered by subjecting thepolymer cement to steam desolventization, followed by drying theresulting polymer crumbs in a hot air tunnel. Alternatively, the polymermay be recovered by directly drying the polymer cement on a drum dryer.The content of the volatile substances in the dried polymer can be below1%, and in other embodiments below 0.5% by weight of the polymer.

Where cis-1,4-polydienes are prepared, they can have a cis-1,4-linkagecontent that is greater than about 60%, in other embodiments greaterthan about 75%, in other embodiments greater than about 90%, and inother embodiments greater than about 95%. Also, these polymers may havea 1,2-linkage content that is less than about 7%, in other embodimentsless than 5%, in other embodiments less than 2%, and in otherembodiments less than 1%. The cis-1,4- and 1,2-linkage contents can bedetermined by infrared spectroscopy. The number average molecular weight(M_(n)) of the polymers may be from about 5,000 to about 200,000, inother embodiments from about 25,000 to about 150,000, and in otherembodiments from about 50,000 to about 120,000, as determined by usinggel permeation chromatography (GPC) calibrated with polystyrenestandards and Mark-Houwink constants for polybutadiene. Thepolydispersity of the polymers may be from about 1.5 to about 5.0, andin other embodiments from about 2.0 to about 4.0.

The functionalized polymers of this invention are particularly useful inpreparing tire components. These tire components can be prepared byusing the functionalized polymers of this invention alone or togetherwith other rubbery polymers. Other rubbery polymers that may be usedinclude natural and synthetic elastomers. The synthetic elastomerstypically derive from the polymerization of conjugated diene monomers.These conjugated diene monomers may be copolymerized with other monomerssuch as vinyl aromatic monomers. Other rubbery polymers may derive fromthe polymerization of ethylene together with one or more α-olefins andoptionally one or more diene monomers.

Useful rubbery polymers include natural rubber, synthetic polyisoprene,polybutadiene, polyisobutylene-co-isoprene, neoprene,poly(ethylene-co-propylene), poly(styrene-co-butadiene),poly(styrene-co-isoprene), and poly(styrene-co-isoprene-co-butadiene),poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene),polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber,epichlorohydrin rubber, and mixtures thereof. These elastomers can havea myriad of macromolecular structures including linear, branched andstar shaped. Other ingredients that are typically employed in rubbercompounding may also be added.

The rubber compositions may include fillers such as inorganic andorganic fillers. The organic fillers include carbon black and starch.The inorganic fillers may include silica, aluminum hydroxide, magnesiumhydroxide, clays (hydrated aluminum silicates), and mixtures thereof.

A multitude of rubber curing agents (also called vulcanizing agents) maybe employed, including sulfur or peroxide-based curing systems. Curingagents are described in Kirk-Othmer, ENCYCLOPEDIA OF CHEMICALTECHNOLOGY, Vol. 20, pgs. 365-468, (3^(rd) Ed. 1982), particularlyVulcanization Agents and Auxiliary Materials, pgs. 390-402, and A. Y.Coran, Vulcanization, ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING,(2^(nd) Ed. 1989), which are incorporated herein by reference.Vulcanizing agents may be used alone or in combination.

Other ingredients that may be employed include accelerators, oils,waxes, scorch inhibiting agents, processing aids, zinc oxide, tackifyingresins, reinforcing resins, fatty acids such as stearic acid, peptizers,and one or more additional rubbers.

These rubber compositions are useful for forming tire components such astreads, subtreads, black sidewalls, body ply skins, bead filler, and thelike. Preferably, the functional polymers are employed in tread andsidewall formulations. In one or more embodiments, these treadformulations may include from about 10% to about 100% by weight, inother embodiments from about 35% to about 90% by weight, and in otherembodiments from about 50% to 80% by weight of the functionalizedpolymer based on the total weight of the rubber within the formulation.

In one or more embodiments, the vulcanizable rubber composition may beprepared by forming an initial masterbatch that includes the rubbercomponent and filler (the rubber component optionally including thefunctionalized polymer of this invention). This initial masterbatch maybe mixed at a starting temperature of from about 25° C. to about 125° C.with a discharge temperature of about 135° C. to about 180° C. Toprevent premature vulcanization (also known as scorch), this initialmasterbatch may exclude vulcanizing agents. Once the initial masterbatchis processed, the vulcanizing agents may be introduced and blended intothe initial masterbatch at low temperatures in a final mixing stage,which preferably does not initiate the vulcanization process.Optionally, additional mixing stages, sometimes called remills, can beemployed between the masterbatch mixing stage and the final mixingstage. Various ingredients including the functionalized polymer of thisinvention can be added during these remills. Rubber compoundingtechniques and the additives employed therein are generally known asdisclosed in The Compounding and Vulcanization of Rubber, in RubberTechnology (2^(nd) Ed. 1973).

The mixing conditions and procedures applicable to silica-filled tireformulations are also well known as described in U.S. Pat. Nos.5,227,425, 5,719,207, 5,717,022, and European Patent No. 890,606, all ofwhich are incorporated herein by reference. In one or more embodiments,where silica is employed as a filler (alone or in combination with otherfillers), a coupling and/or shielding agent may be added to the rubberformulation during mixing. Useful coupling and shielding agents aredisclosed in U.S. Pat. Nos. 3,842,111, 3,873,489, 3,978,103, 3,997,581,4,002,594, 5,580,919, 5,583,245, 5,663,396, 5,674,932, 5,684,171,5,684,172 5,696,197, 6,608,145, 6,667,362, 6,579,949, 6,590,017,6,525,118, 6,342,552, and 6,683,135, which are incorporated herein byreference. In one embodiment, the initial masterbatch is prepared byincluding the functionalized polymer of this invention and silica in thesubstantial absence of coupling and shielding agents.

Where the vulcanizable rubber compositions are employed in themanufacture of tires, these compositions can be processed into tirecomponents according to ordinary tire manufacturing techniques includingstandard rubber shaping, molding and curing techniques. Typically,vulcanization is effected by heating the vulcanizable composition in amold; e.g., it may be heated to about 140 to about 180° C. Cured orcrosslinked rubber compositions may be referred to as vulcanizates,which generally contain three-dimensional polymeric networks that arethermoset. The other ingredients, such as processing aides and fillers,may be evenly dispersed throughout the vulcanized network. Pneumatictires can be made as discussed in U.S. Pat. Nos. 5,866,171, 5,876,527,5,931,211, and 5,971,046, which are incorporated herein by reference.

In order to demonstrate the practice of the present invention, thefollowing examples have been prepared and tested. The examples shouldnot, however, be viewed as limiting the scope of the invention. Theclaims will serve to define the invention.

EXAMPLES Example 1 Synthesis of Unmodified cis-1,4-Polybutadiene(Control Polymer)

To a 2-gallon reactor equipped with turbine agitator blades was added1605 g of hexane and 2861 g of 22.2 wt % butadiene in hexane. Apreformed catalyst was prepared by mixing 7.35 mL of 4.32 Mmethylaluminoxane in toluene, 1.54 g of 22.2 wt % 1,3-butadiene inhexane, 0.59 mL of 0.537 M neodymium versatate in cyclohexane, 6.67 mLof 1.0 M diisobutylaluminum hydride in hexane, and 1.27 mL of 1.0 Mdiethylaluminum chloride in hexane. The catalyst was aged for 15 minutesand charged into the reactor. The reactor jacket temperature was thenset to 65° C. Forty-five minutes after addition of the catalyst, thepolymerization mixture was cooled to room temperature. The resultingpolymer cement was coagulated with 12 liters of isopropanol containing 5g of 2,6-di-tert-butyl-4-methylphenol and then drum-dried. The Mooneyviscosity (ML₁₊₄) of the resulting polymer was determined to be 27.3 at100° C. by using a Monsanto Mooney viscometer with a large rotor, aone-minute warm-up time, and a four-minute running time. As determinedby gel permeation chromatography (GPC), the polymer had a number averagemolecular weight (M_(n)) of 112,400, a weight average molecular weight(M_(w)) of 206,800, and a molecular weight distribution (M_(w)/M_(n)) of1.84. The infrared spectroscopic analysis of the polymer indicated acis-1,4-linkage content of 94.7%, a trans-1,4-linkage content of 4.8%,and a 1,2-linkage content of 0.5%.

The cold-flow resistance of the polymer was measured by using a Scottplasticity tester. Approximately 2.6 g of the polymer was molded at 100°C. for 20 minutes, into a cylindrical button with a diameter of 15 mmand a height of 12 mm. After cooling down to room temperature, thebutton was removed from the mold and placed in a Scott plasticity testerat room temperature. A 5-kg load was applied to the specimen. After 8minutes, the residual gauge (i.e., sample thickness) was measured andtaken as an indication of the cold-flow resistance of the polymer.Generally, a higher residual gauge value indicates better cold-flowresistance.

The properties of the polymer are summarized in Table 1.

TABLE 1 Physical Properties of Unmodified and Modifiedcis-1,4-Polybutadiene Example No. Example 5 Example 1 Example 2 Example3 Example 4 (comparative) Polymer type unmodified unmodified BPyMEDA-TBTAEA- BBEDA- modified modified modified Mooney viscosity 27.3 43.642.6 37.3 31.0 M_(n) 112,400 139,500 122,400 116,200 114,600 M_(w)206,800 248,800 225,600 229,200 219,600 M_(w)/M_(n) 1.84 1.78 1.84 1.971.92 Microstructure: % cis 94.7 95.1 94.7 94.7 94.7 % trans 4.8 4.4 4.84.8 4.8 % vinyl 0.5 0.5 0.5 0.5 0.5 Cold-flow gauge 1.69 2.01 2.50 2.011.78 (mm at 8 min.)

Example 2 Synthesis of Unmodified cis-1,4-Polybutadiene (ControlPolymer)

To a 2-gallon reactor equipped with turbine agitator blades was added1428 g of hexane and 3038 g of 20.9 wt % butadiene in hexane. Apreformed catalyst was prepared by mixing 6.03 mL of 4.32 Mmethylaluminoxane in toluene, 1.35 g of 20.9 wt % 1,3-butadiene inhexane, 0.48 mL of 0.537 M neodymium versatate in cyclohexane, 5.47 mLof 1.0 M diisobutylaluminum hydride in hexane, and 1.04 mL of 1.0 Mdiethylaluminum chloride in hexane. The catalyst was aged for 15 minutesand charged into the reactor. The reactor jacket temperature was thenset to 65° C. Sixty-five minutes after addition of the catalyst, thepolymerization mixture was cooled to room temperature. The resultingpolymer cement was coagulated with 12 liters of isopropanol containing 5g of 2,6-di-tert-butyl-4-methylphenol and then drum-dried. Theproperties of the resulting polymer are summarized in Table 1.

Example 3 Synthesis of cis-1,4-Polybutadiene Modified withN,N′-Bis(2-pyridylmethylidene)ethylenediamine (BPyMEDA)

To a 2-gallon reactor equipped with turbine agitator blades was added1946 g of hexane and 2520 g of 25.2 wt % butadiene in hexane. Apreformed catalyst was prepared by mixing 7.35 mL of 4.32 Mmethylaluminoxane in toluene, 1.36 g of 25.2 wt % 1,3-butadiene inhexane, 0.59 mL of 0.537 M neodymium versatate in cyclohexane, 6.67 mLof 1.0 M diisobutylaluminum hydride in hexane, and 1.27 mL of 1.0 Mdiethylaluminum chloride in hexane. The catalyst was aged for 15 minutesand charged into the reactor. The reactor jacket temperature was thenset to 65° C. Sixty minutes after addition of the catalyst, thepolymerization mixture was cooled to room temperature. 424 g of theresulting unmodified polymer cement was transferred from the reactor toa nitrogen-purged bottle, followed by addition of 1.78 mL of 1.00 MN,N′-Bis(2-pyridylmethylidene)ethylenediamine (BPyMEDA) in toluene. Thebottle was tumbled for 25 minutes in a water bath maintained at 65° C.The resulting mixture was coagulated with 3 liters of isopropanolcontaining 0.5 g of 2,6-di-tert-butyl-4-methylphenol and thendrum-dried. The properties of the resulting BPyMEDA-modified polymer aresummarized in Table 1.

Example 4 Synthesis of cis-1,4-Polybutadiene Modified withN,N′,N″-tris(benzylidene)-tris(2-aminoethyl)amine (TBTAEA)

cis-1,4-Polybutadiene modified withN,N′,N″-tris(benzylidene)-tris(2-aminoethyl)amine (TBTAEA) was preparedby using a procedure similar to that described in Example 3 andreplacing BPyMEDA with TBTAEA. The properties of the resultingTBTAEA-modified polymer are summarized in Table 1.

Example 5 (Comparative Example) Synthesis of cis-1,4-PolybutadieneModified with N,N′-Bis(benzylidene)ethylenediamine (BBEDA)

cis-1,4-Polybutadiene modified with N,N′-bis(benzylidene)ethylenediamine(BBEDA) was prepared by using a procedure similar to that described inExample 3 and replacing BPyMEDA with BBEDA. The properties of theresulting BBEDA-modified polymer are summarized in Table 1.

In FIG. 1, the cold-flow resistance of the unmodified and modifiedpolymers synthesized in Examples 1-5 is plotted against the polymerMooney viscosity. The data indicate that, at the same polymer Mooneyviscosity, the BPyMEDA- and TBTAEA-modified polymers show higherresidual cold-flow gauge values and accordingly better cold-flowresistance than the unmodified polymer. In contrast, BBEDA-modifiedpolymer shows no improvement in cold-flow resistance over unmodifiedpolymer.

Examples 6-10 Compounding Evaluation of BPyMEDA-, TBTAEA-, andBBEDA-Modified Polymers vs. Modified Polymer

The polymer samples produced in Examples 1-5 were evaluated in a carbonblack filled rubber compound. The compositions of the vulcanizates arepresented in Table 2, wherein the numbers are expressed as parts byweight per hundred parts by weight of rubber (phr).

TABLE 2 Compositions of Rubber Vulcanizates Example No. Example 10Example 6 Example 7 Example 8 Example 9 (comparative) Polymer usedExample 1 Example 2 Example 3 Example 4 Example 5 Polymer typeunmodified unmodified BPyMEDA- TBTAEA- BBEDA- modified modified modifiedPolymer (phr) 80 80 80 80 80 Polyisoprene (phr) 20 20 20 20 20 Carbonblack (phr) 50 50 50 50 50 Oil (phr) 10 10 10 10 10 Wax (phr) 2 2 2 2 2Antioxidant (phr) 1 1 1 1 1 Stearic acid (phr) 2 2 2 2 2 Zinc oxide(phr) 2.5 2.5 2.5 2.5 2.5 Accelerators (phr) 1.3 1.3 1.3 1.3 1.3 Sulfur(phr) 1.5 1.5 1.5 1.5 1.5 Total 170.3 170.3 170.3 170.3 170.3

The Mooney viscosity (ML₁₊₄) of the uncured compound was determined at130° C. by using a Alpha Technologies Mooney viscometer with a largerotor, a one-minute warm-up time, and a four-minute running time. ThePayne effect data (ΔG′) and hysteresis data (tan δ) of the vulcanizateswere obtained from a dynamic strain sweep experiment, which wasconducted at 50° C. and 15 Hz with strain sweeping from 0.1% to 20%. ΔG′is the difference between G′ at 0.1% strain and G′ at 20% strain. Thephysical properties of the vulcanizates are summarized in Table 3 andFIG. 2.

TABLE 3 Physical Properties of Rubber Vulcanizates Example No. Example10 Example 6 Example 7 Example 8 Example 9 (comparative) Polymer usedExample 1 Example 2 Example 3 Example 4 Example 5 Polymer typeunmodified unmodified BPyMEDA- TBTAEA- BBEDA- modified modified modifiedCompound ML 53.3 65.2 74.2 82.1 69.9 at 130° C. ΔG′ (MPa) 2.30 2.08 1.251.48 1.48 tanδ at 50° C., 0.125 0.113 0.0809 0.0858 0.0926 3% strain

As can be seen in Table 3 and FIG. 2, the BPyMEDA-, TBTAEA-, andBBEDA-modified polymers give lower tan δ at 50° C. than the unmodifiedpolymer, indicating that the modification with BPyMEDA, TBTAEA, andBBEDA reduces hysteresis. The BPyMEDA-, TBTAEA-, and BBEDA-modifiedpolymers also give lower ΔG′ than the unmodified polymer, indicatingthat the Payne Effect has been reduced due to the stronger interactionbetween the modified polymers and carbon black. In addition, acomparison of the results obtained in Example 8 with those obtained inExample 10 indicates that the polymer functionalized with BPyMEDA (abis-imine compound containing heterocyclic groups, i.e., pyridyl groups)gives greater reduction in hysteresis and the Payne Effect than thepolymer modified with BBEDA (a bis-imine compound containingnon-heterocyclic groups, i.e., phenyl groups).

Various modifications and alterations that do not depart from the scopeand spirit of this invention will become apparent to those skilled inthe art. This invention is not to be duly limited to the illustrativeembodiments set forth herein.

1. A method for preparing a functionalized polymer, the method comprising the steps of: (i) polymerizing conjugated diene monomer by employing a lanthanide-based catalyst to form a reactive polymer; and (ii) reacting the reactive polymer with a tris-imine compound selected from the group consisting of N,N′,N″-tris(benzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(cyclohexylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(cyclopentylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-dimethylaminobenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-diethylaminobenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-di-n-butylaminobenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-methoxybenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-methoxybenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-methoxybenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-pyridylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-pyridylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-pyridylmethylidene)-tris(2-aminoethyl)amine, N-(2-pyridylmethylidene)-N′,N″-bis(benzylidene)-tris (2-aminoethyl)amine, N,N′-bis(2-pyridylmethylidene)-N″-(benzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(pyrazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-pyrimidinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-pyridazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-pyrrolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-imidazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-3-pyrazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-furylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-furylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-thienylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-thienylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-oxazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-isoxazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-thiazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-isothiazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-1,2,3-triazol-4-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-1,2,4-triazol-5-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1,2,3-oxadiazol-4-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1,3,4-oxadiazol-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1,3,5-triazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-pyrrolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-imidazolin-2-ylmethylidene)-tris (2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-pyrazolin-3-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-oxazolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-thiazolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-isothiazolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-quinolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-isoquinolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methylindol-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-methylisoindol-1-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-phthalazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-quinazolinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-quinoxalinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-cinnolinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-benzothiazolylmethylidene)-tris(2-aminoethyl)amine, and mixtures thereof.
 2. The method of claim 1, where the molar ratio of the tris-imine compound to the lanthanide metal of the lanthanide-based catalyst is from about 1:1 to about 200:1.
 3. The method of claim 1, where the molar ratio of the tris-imine compound to the lanthanide metal of the lanthanide-based catalyst is from about 5:1 to about 150:1.
 4. The method of claim 1, where the lanthanide-based catalyst is formed by combining a lanthanide compound, an alkylating agent, and optionally a halogen-containing compound, with the proviso that the lanthanide compound or the alkylating agent include a labile halogen atom in the absence of the optional halogen-containing compound.
 5. The method of claim 4, where the alkylating agent includes an aluminoxane and an organoaluminum compound represented by the formula AlR_(n)X_(3−n), where each R, which may be the same or different, is a mono-valent organic group that is attached to the aluminum atom via a carbon atom, where each X, which may be the same or different, is a hydrogen atom, a halogen atom, a carboxylate group, an alkoxide group, or an aryloxide group, and where n is an integer of 1 to
 3. 6. The method of claim 1, where said step of reacting the reactive polymer with the tris-imine compound occurs before the reactive polymer is quenched.
 7. A method for preparing a functionalized polymer, the method comprising the steps of: (i) introducing conjugated diene monomer and a lanthanide-based catalyst to form a polymerization mixture; and (ii) adding a polyimine compound to the polymerization mixture, where the polyimine compound is a tris-imine selected from the group consisting of N,N′,N″-tris (benzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(cyclohexylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(cyclopentylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-dimethylaminobenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-diethylaminobenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-di-n-butylaminobenzylidene)-tris (2-aminoethyl)amine, N,N′,N″-tris(2-methoxybenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-methoxybenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-methoxybenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-pyridylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-pyridylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-pyridylmethylidene)-tris(2-aminoethyl)amine, N-(2-pyridylmethylidene)-N′,N″-bis(benzylidene)-tris(2-aminoethyl)amine, N,N′-bis(2-pyridylmethylidene)-N″-(benzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris (pyrazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-pyrimidinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-pyridazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-pyrrolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-imidazolylmethylidene)-tris (2-aminoethyl)amine, N,N′,N″-tris(1-methyl-3-pyrazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-furylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-furylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-thienylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-thienylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-oxazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-isoxazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-thiazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-isothiazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-1,2,3-triazol-4-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-1,2,4-triazol-5-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1,2,3-oxadiazol-4-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1,3,4-oxadiazol-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1,3,5-triazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-pyrrolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-imidazolin-2-ylmethylidene)-tris (2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-pyrazolin-3-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-oxazolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-thiazolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-isothiazolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-quinolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-isoquinolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methylindol-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-methylisoindol-1-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-phthalazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-quinazolinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-quinoxalinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-cinnolinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-benzothiazolylmethylidene)-tris(2-aminoethyl)amine, and mixtures thereof.
 8. A functionalized polymer prepared by a method comprising the steps of: (i) polymerizing conjugated diene monomer by employing a lanthanide-based catalyst to form a reactive polymer; and (ii) reacting the reactive polymer with a a tris-imine compound selected from the group consisting of N,N′,N″-tris(benzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris (cyclohexylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris (cyclopentylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-dimethylaminobenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-diethylaminobenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-di-n-butylaminobenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-methoxybenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-methoxybenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-methoxybenzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-pyridylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-pyridylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(4-pyridylmethylidene)-tris(2-aminoethyl)amine, N-(2-pyridylmethylidene)-N′,N″-bis(benzylidene)-tris (2-aminoethyl)amine, N,N′-bis(2-pyridylmethylidene)-N″-(benzylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris (pyrazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-pyrimidinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-pyridazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-pyrrolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-imidazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-3-pyrazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-furylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-furylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-thienylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-thienylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-oxazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-isoxazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-thiazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-isothiazolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-1,2,3-triazol-4-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-1,2,4-triazol-5-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1,2,3-oxadiazol-4-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1,3,4-oxadiazol-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1,3,5-triazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-pyrrolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-imidazolin-2-ylmethylidene)-tris (2-aminoethyl)amine, N,N′,N″-tris(1-methyl-2-pyrazolin-3-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-oxazolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-thiazolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-isothiazolin-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-quinolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-isoquinolylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-methylindol-2-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-methylisoindol-1-ylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(1-phthalazinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-quinazolinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-quinoxalinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(3-cinnolinylmethylidene)-tris(2-aminoethyl)amine, N,N′,N″-tris(2-benzothiazolylmethylidene)-tris(2-aminoethyl)amine, and mixtures thereof.
 9. A method for preparing a functionalized polymer, the method comprising the steps of: (i) polymerizing conjugated diene monomer by employing a lanthanide-based catalyst to form a reactive polymer; and (ii) reacting the reactive polymer with a polyimine compound, where the polyimine compound is defined by the formula II:

where n is integer of 2 or 3, R¹ is a divalent organic group, R³ is a divalent organic group or a chemical bond, μ is a polyvalent atom or organic group having a valence equal to n, θ is a heterocyclic group, and R⁴ is a hydrogen atom, a monovalent organic group, or a heterocyclic group.
 10. A method for preparing a functionalized polymer, the method comprising the steps of: (i) introducing conjugated diene monomer and a lanthanide-based catalyst to form a polymerization mixture; and (ii) adding a polyimine compound to the polymerization mixture, where the polyimine compound is defined by the formula II:

where n is integer of 2 or 3, R¹ is a divalent organic group, R³ is a divalent organic group or a chemical bond, μ is a polyvalent atom or organic group having a valence equal to n, θ is a heterocyclic group, and R⁴ is a hydrogen atom, a monovalent organic group, or a heterocyclic group.
 11. A functionalized polymer prepared by a method comprising the steps of: (i) polymerizing conjugated diene monomer by employing a lanthanide-based catalyst to form a reactive polymer; and (ii) reacting the reactive polymer with a polyimine compound, where the polyimine compound is defined by the formula II:

where n is an integer of 2 or more, R¹ is a divalent organic group, R³ is a divalent organic group or a chemical bond, μ is a polyvalent atom or organic group having a valence equal to n, θ is a heterocyclic group, and R⁴ is a hydrogen atom, a monovalent organic group, or a heterocyclic group.
 12. The method of claim 9, where the molar ratio of the polyimine compound to the lanthanide metal of the lanthanide-based catalyst is from about 1:1 to about 200:1.
 13. The method of claim 9, where the molar ratio of the polyimine compound to the lanthanide metal of the lanthanide-based catalyst is from about 5:1 to about 150:1.
 14. The method of claim 9, where the lanthanide-based catalyst is formed by combining a lanthanide compound, an alkylating agent, and optionally a halogen-containing compound, with the proviso that the lanthanide compound or the alkylating agent include a labile halogen atom in the absence of the optional halogen-containing compound.
 15. The method of claim 14, where the alkylating agent includes an aluminoxane and an organoaluminum compound represented by the formula AlR_(n)X_(3−n), where each R, which may be the same or different, is a mono-valent organic group that is attached to the aluminum atom via a carbon atom, where each X, which may be the same or different, is a hydrogen atom, a halogen atom, a carboxylate group, an alkoxide group, or an aryloxide group, and where n is an integer of 1 to
 3. 16. The method of claim 9, where said step of reacting the reactive polymer with the polyimine compound occurs before the reactive polymer is quenched.
 17. The method of claim 9, where the polyimine is a bis-imine compound selected from the group consisting of N,N′-bis(2-pyridylmethylidene)ethylenediamine, N-(2-pyridylmethylidene)-N′-(benzylidene)ethylenediamine, N,N′-bis(3-pyridylmethylidene)ethylenediamine, N-(3-pyridylmethylidene)-N′-(benzylidene)ethylenediamine, N,N′-bis(4-pyridylmethylidene)ethylenediamine, N-(4-pyridylmethylidene)-N′-(benzylidene)ethylenediamine, N,N′-bis(pyrazinylmethylidene)ethylenediamine, N,N′-bis(2-pyrimidinylmethylidene)ethylenediamine, N,N′-bis(3-pyridazinylmethylidene)ethylenediamine, N,N′-bis(1-methyl-2-pyrrolylmethylidene)ethylenediamine, N,N′-bis(1-methyl-2-imidazolylmethylidene)ethylenediamine, N,N′-bis(1-methyl-3-pyrazolylmethylidene)ethylenediamine, N,N′-bis(2-furylmethylidene)ethylenediamine, N,N′-bis(3-furylmethylidene)ethylenediamine, N,N′-bis(2-thienylmethylidene)ethylenediamine, N,N′-bis(3-thienylmethylidene)ethylenediamine, N,N′-bis(2-oxazolylmethylidene)ethylenediamine, N,N′-bis(3-isoxazolylmethylidene)ethylenediamine, N,N′-bis(2-thiazolylmethylidene)ethylenediamine, N,N′-bis(3-isothiazolylmethylidene)ethylenediamine, N,N′-bis(1-methyl-1,2,3-triazol-4-ylmethylidene)ethylenediamine, N,N′-bis(1-methyl-1,2,4-triazol-5-ylmethylidene)ethylenediamine, N,N′-bis(1,2,3-oxadiazol-4-ylmethylidene)ethylenediamine, N,N′-bis(1,3,4-oxadiazol-2-ylmethylidene)ethylenediamine, N,N′-bis(1,3,5-triazinylmethylidene)ethylenediamine, N,N′-bis(1-methyl-2-pyrrolin-2-ylmethylidene)ethylenediamine, N,N′-bis(1-methyl-2-imidazolin-2-ylmethylidene)ethylenediamine, N,N′-bis(1-methyl-2-pyrazolin-3-ylmethylidene)ethylenediamine, N,N′-bis(2-oxazolin-2-ylmethylidene)ethylenediamine, N,N′-bis(2-thiazolin-2-ylmethylidene)ethylenediamine, N,N′-bis(2-isothiazolin-2-ylmethylidene)ethylenediamine, N,N′-bis(2-quinolylmethylidene)ethylenediamine, N,N′-bis(1-isoquinolylmethylidene)ethylenediamine, N,N′-bis(1-methylindol-2-ylmethylidene)ethylenediamine, N,N′-bis(2-methylisoindol-1-ylmethylidene)ethylenediamine, N,N′-bis(1-phthalazinylmethylidene)ethylenediamine, N,N′-bis(2-quinazolinylmethylidene)ethylenediamine, N,N′-bis(2-quinoxalinylmethylidene)ethylenediamine, N,N′-bis(3-cinnolinylmethylidene)ethylenediamine, N,N′-bis(2-benzothiazolylmethylidene)ethylenediamine, N,N′-bis(2-pyridylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(3-pyridylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(4-pyridylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(pyrazinylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-pyrimidinylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(3-pyridazinylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1-methyl-2-pyrrolylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1-methyl-2-imidazolylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1-methyl-3-pyrazolylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-furylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(3-furylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-thienylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(3-thienylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-oxazolylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(3-isoxazolylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-thiazolylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(3-isothiazolylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1-methyl-1,2,3-triazol-4-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1-methyl-1,2,4-triazol-5-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1,2,3-oxadiazol-4-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1,3,4-oxadiazol-2-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1,3,5-triazinylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1-methyl-2-pyrrolin-2-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1-methyl-2-imidazolin-2-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1-methyl-2-pyrazolin-3-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-oxazolin-2-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-thiazolin-2-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-isothiazolin-2-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-quinolylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1-isoquinolylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1-methylindol-2-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-methylisoindol-1-ylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(1-phthalazinylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-quinazolinylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-quinoxalinylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(3-cinnolinylmethylidene)-1,2-cyclohexanediamine, N,N′-bis(2-benzothiazolylmethylidene)-1,2-cyclohexanediamine, and mixtures thereof. 